GlueX Physics Photoproduction
Contents
GlueX Physics
Review Papers
Mesons in the Quark Model
Exotic Quantum Number Mesons
Lattice QCD Calculations
Photoproduction
Linear Polarization
In GlueX, the linearly polarized photons will be produced by coherent bremstrahlung. In this process, the photons in the coherent scattering peak from the crystal radiator are polarized. The direction of the polarization vector (in the lab) depends on the orientation of the crystal, but is fixed (in the lab). The degree of polarization of the coherent peak depends on the ratio of the photon energy to the end-point energy.
In the photo-production of mesons (via t-channel processes), the relevant
Reference Frames
The lab frame is typically taken with the z-axis along the incoming photon direction and the y-axis normal to the surface of the Earth. The x-axis is then taken . Related to the lab frame is the center of mass frame. The coordinate directions are the same, but the two frames are connected by a boost along the z-axis with and the total energy in the center of mass is .
In t-channel photo production, a particle X is produced recoiling against an out-going proton. The Mandelstam t is given as where k is the photon momentum and is the 4-momentum of the produced particle .
References
Experimental Papers
- Differential cross sections and spin density matrix elements for γp → ω p, M. Williams, et al., (CLAS Collaboration), Phys. Rev. C80, 065208 (2009), arXiv.
- Partial wave analysis of γ p → ω p and the search for nucleon resonances, M. Williams, et al., (CLAS Collaboration), Phys. Rev. C80, 065209 (2009), arXiv.
- Differential cross sections for the reactions γ p → η p and γ p → η' p, M. Williams, et al., (CLAS Collaboration), submitted to Phys. Rev. C (2009), arXiv.
- On the Analysis of Vector-Meson Production by Polarized Photons,K. Schilling, P. Seyboth and G. Wolf, Nucl. Phys. B15 (1970), 397-412, pdf
- Bubble-Chamber Study of Photoproduction by 2.8 and 4.7 GeV Polarized Photons. I. Cross-Section Determination and Production of ρ0 and Δ++ in the Reaction γp → pπ+π- J. Ballam et al., Phys. Rev. D5 (1972), 545-589, pdf.
- Vector-Meson Production by Polarized Photons at 2.8, 4.7 and 9.3 GeV, J. Ballam et al., Phys. Rev. D7 (1973), 3150-3177, pdf.
- Spin-Parity Analysis of ρ' in the reaction γ p → π+ π+ π- π-p at 9 to 18 GeV, Joseph C.H. Park, Nucl. Phys. B58, (1973), 45-54, pdf.
- High-Energy Production and Decay of vector and Tensor Mesons, A.C. Irving and C. Michel, Nucl. Phys. B82, (1974), 282-325, pdf.
- The Reaction γ p → π+ π- π+ π- p at High-energy and dissociation into 4π, M. Davier, et al., Nucl. Phys. B58 (1973), 31-44, pdf.
Theoretical Papers
- Generalized Parton Distributions (GPD)